For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningInstallation Procedure
Cut the front end upper tie bar in corresponding locations to fit the
remaining original panel. The sectioning joint should be trimmed
to allow a gap of one-and-one-half-times the metal thickness at the
sectioning joint.
Create a 50 mm (2 in) backing plate from the unused portion of ...
Installation Procedure
Cut the front compartment front rail in corresponding locations to fit
the remaining original panel. The sectioning joint should be
trimmed to allow a gap of one-and-one-half-times the metal thickness at the
sectioning joint.
Create a 50 mm (2 in) backing plate from the unused porti ...
Vehicle Certification, Tire Placard, Anti-Theft, and Service Parts ID Label
Vehicle Certification Label
The vehicle certification label is located on the driver door and displays
the following assessments:
Gross Vehicle Weight Rating (GVWR)
Gross Axle Weight Rating (GAWR), front and rear
The gross vehicle weight (GVW) is the weight of the vehicle and everything it ...